Question

class Solution:
    # @param n, an integer
    # @return a string
    def countAndSay(self, n):
        def f(string):
            a = []
            count_1 = 1
            count_2 = 1
            s = string[1:] + 'e'                                    #calculate i from string[1](this is to disregard the case of string[0]), meanwhile add 'e' to notify the end of the string
            for i, j in enumerate(s):

                if j == '1':
                    if string[i] == '1':                            #check whether the last member in string is the same as j
                        count_1 += 1                                #if so, count_1 add 1, save for further list appending
                    else:
                        count_1 = 1                                 #reset the count if last character does not match with j
                        a.append[(str(count_2) + '2')]              

                if j == '2':
                    if string[i] == '2':
                        count_2 += 1
                    else:
                        count_2 = 1
                        a.append[(str(count_1) + '1')]

                if j == 'e':                                         #j=='e' if the iteration reach the end, and it is the right time for adding the final member of the expected list
                    if string[i] == '1':                            
                        a.append[(str(count_1) + '1')]
                    if string[i] == '2':
                        a.append[(str(count_2) + '2')]

                return ''.join(list)

        def seq(n): 
            if n == 1:
                return '1'
            if n == 2:
                return '11'
            if n == 3:
                return '21'
            else:
                return f(seq(n-1))

        return seq(n)

这是来自leetcode的问题的解决方案： https://leetcode.com/problems/count-and-say/

它通知我：

运行时错误消息：第17行：TypeError：   'builtin_function_or_method'对象没有属性' getitem '

上次执行的输入：4

第17行如下：

a.append[(str(count_2) + '2')]

请，我是一个完全新手，不知道如何解决这个问题。另外，我希望你也改进我的代码。非常感谢你。

Answer 1

嗯，显然，第17行看起来应该是

a.append(str(count_2) + '2')

请参阅documentation on lists

当您使用方括号（a.append[key]）时，Python会尝试在__getitem__上调用a.append方法

一个python解决方案＆＃34;计数并说＆＃34;来自leetcode出错了

1 个答案: